The present invention relates to a reflection-type color liquid crystal display apparatus. In particular, the present invention relates to a technique for liquid crystal display capable of realizing color reproduction at all of gray scales.
A reflection type liquid crystal display is a display having a feature of low power consumption inherent to liquid crystal. Further, the reflection type liquid crystal display Is a device indispensable for apparatuses that are intensive in demand for drive time such as a portable information terminal device or the like. However, according to a reflection type liquid crystal display of black and white display currently constituting the main stream, there poses a problem in which an amount of information which can be displayed thereby is limited, and further it is difficult to deal with image information thereby. A reflection type color liquid crystal display having a high performance is desired for expanding markets of a portable information terminal device or the like in the future.
In Japanese Patent Laid-Open No. Hei 10-154817, there is disclosed a cell parameter in the case of twist angles of 45°, 63° and 90°. Further, in Japanese Patent Laid-Open No. Hei 6-11711, there is disclosed a reflection type liquid crystal display apparatus having a mirror surface electrode having irregularities surfaces of which are smooth and comprising a polarizer, a liquid crystal element and an optical phase compensating member. According to the reflection type crystal display apparatus, retardations of the crystal element and the optical phase compensating member are selected such that a light transmitting state is constituted when an amount obtained by dividing a difference between retardation of the liquid crystal element and retardation of the optical phase compensating member by wavelength, is m/2±0.1 where m is a positive integer and a light blocking state is constituted when the amount is 0.25±m/2±0.1.
In either of the above-described conventional techniques, although some achromatization in white or black display is taken into consideration to some degree, achromatization in white display as well as black display and over all of gray scales is not taken into consideration. Therefore, when gradation display continuously changing from white to black is carried out in a liquid crystal display under such a condition, coloring is caused at an intermediary gray scale, resulting in a deterioration in display quality.